Hot isostatic pressing of metallic or ceramic powders, so called HIP or HIPPING is a commonly used manufacturing process for various components. In the HIP manufacturing process a capsule which defines the shape of the article is filled with a metal or ceramic powder of desired composition. The capsule is evacuated, sealed and thereafter subjected to increased temperature and pressure whereby the powder is densified into a compact body.
Some components comprise internal cavities, for example cooling channels. However, it is difficult to achieve components having curved internal channels with conventional methods such as milling or boring in metallic work pieces.
The documents WO2005/049251 and DE4426544 describe HIP methods for manufacture of components having internal channels. The internal channels are formed from pre-forms that are arranged within a mould that defines the shape of the article. The mould is filled with metallic powder and is heated under isostatic pressure whereby the metallic powder densifies to a compact article. The pre-forms are thereafter removed whereby an internal cavity remains in the article. It is also known to use preformed tubes to form the internal cavities in the component. The tubes remain in the compacted article after the heating and compacting step.
A problem with the above mentioned methods is that it is difficult to achieve high accuracy of the position of the internal cavities in the final component. This is mainly due to that the embedded channel forming pre-form moves when the powder is heated and subjected to high isostatic pressure during manufacture of the component.
Thus, it is an object of the present invention to provide an improved method for manufacture a component having at least one internal cavity which method solves at least one of the aforementioned problems.